<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="鸿蒙" content="鸿蒙培训"/>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title id="title">欢迎学习HTML</title>
    <meta http-equiv="Refresh" content="3;url=https://www.baidu.com" />
    <base target="_blank"/>
</head>
<body>
    <a href="http://www.baidu.com">百度</a>
    <div>原网址已经停止维护 <span id="count">3</span>秒内前往新地址</div>
</body>

<script>
    document.getElementById("title").innerHTML = "欢迎来到千锋";
    let countSpan = document.getElementById("count");
    let  num = 3;
    //定时器
    setInterval(()=>{
        num = num -1;
        countSpan.innerHTML = num;
    },1000);
</script>
</html>